Previous Final KB Questions

Question 1

Explain the basic premise of flotation.

Answer 1

Flotation is a technique that separates particles based on their surface hydrophobicity.

Question 2

Schematic process of flotation and explain

Answer 2

1. During this process, air is injected into the cell through a hollow shaft, at the bottom of the cell, an impeller is rotating at high speed (around 1000 rpm) to produce air bubbles.
2. As air bubbles rise up, hydrophobic particles would attach onto bubbles and get carried to the top froth zone, and then collected as concentrate.
3. Whereas the hydrophilic particles would remain in the slurry and report to the tailing stream

Question 3

Give and explain every reagent types (5) used within flotation.

Answer 3

Flotation reagents include:
1. pH regulators (to adjust pH of slurry),

2. Frother (to produce fine bubbles and maintain stable froth. also slow down bubble rising velocity for better particle-bubble encounter),
3. Collectors (adsorb onto mineral surface to introduce surface hydrophobicity)
4. Activators (add additional adsorption sites for collectors),
5. Depressants (prevent adsorption of collectors onto mineral surface)

Question 4

Discuss the importance of the comminution process on flotation performance.

Answer 4

Prior to flotation, comminution is an important stage. It could improve liberation of minerals, and break particles down to a suitable size range for flotation

Question 5

What are the limitations of flotations in 2? (1 limitation for real, 2 eco bullshit)

Answer 5

1. As for the limitation of flotation, it has problem to process ultra fine particles due to their low mass and high surface area, which results in high reagent consumption, low collision with air bubbles, slow kinetics, and poor attachment.
2. Flotation also requires consumption of chemical reagents, which could be detrimental to the environment. In addition, large amount of water would be required, and wastewater treatment could make flotation less eco-friendly.